At least one child is sexually abused by a school employee every day in New York City schools, a Post investigation has found.

Equally as disturbing is that one-third of the employees accused of sex abuse are repeat offenders, who’ve already been cited for inappropriate behavior by school officials.

“It has reached critical mass,” said Schools Special Investigator Edward Stancik. “I think it’s very hard for anybody to deny that we have a real problem.”

The Post has analyzed 117 cases of sexual abuse substantiated by Stancik’s office over a 2 ½ year period – from January 1999 to June 2001 – to determine how offenders are picking off city kids.

Among the observations, The Post investigation has found that more than 60 percent of employees accused of sexual abuse – mostly tenured teachers – were transferred to desk jobs at district offices located inside schools. Forty percent of those transferred suspects were repeat offenders.

Problem teachers, who sometimes get away with a sexual offense, are surreptitiously transferred to other schools – a practice known as “passing the garbage.”

BOE President Ninfa Segarra was devastated by the outcome of The Post report.

She said – to her knowledge – no agency has ever bothered to analyze sex abuse inside city schools.

“My gut reaction as a mother is that that number is pretty high and it puts a lot of kids in danger,” she said of the number of repeat offenders working with children.

Many blame the United Federation of Teachers because it vigorously defends its accused members. One union source said the UFT is legally bound to protect them – even when it knows the employee is a “pervert.”

UFT President Randi Weingarten said the BOE, Stancik and the city’s blaming of the UFT for the sex abuse issue is “outrageous.” She charges the BOE has adopted a “bunker mentality,” when confronted with real problems.

She said all teachers deserve “fair and due process” but refused to comment directly on defending teachers who are repeatedly accused of being pedophiles. A BOE source said it takes an average of about 20 months and numerous state arbitrator hearings just to get rid of a suspected sex abuser.

“To say it’s an imperfect process is putting it kindly,” the source said.

Since sex abuse is one of the most under-reported crimes in schools, “the percentage of cases reported is substantially lower than the cases that actually occurred,” Stancik said.

And even though he’s seen some improvements to prevent abuse over the years, Stancik said much more needs to be done.

“I have not seen a commitment to do more than just what is necessary, as if to appear that they [the BOE] are paying attention.”

Other Post findings include:

Out of the 117 cases, more than 212 children were victims because in 45 percent of the cases an offender attacked more than one student. Repeat offenders made up nearly half of the suspects who attacked more than one kid.

In nearly 16 percent of the cases, school officials delayed reporting the offense or tried to cover it up.

Paraprofessionals and school aides are among the top sex offenders – nearly 20 percent. Math teachers, some of who tutored and later tried to seduce students through the Internet, made up nearly 10 percent of the offenders. Special Ed teachers also made up 10 percent of the offenders.

The average victim is a 15-year-old female high school student in Brooklyn, where 36 percent of the abuse cases occurred. The average age of an offender is 39.

Seventy-five percent of the victims are girls.

Nearly 20 percent of the offenders are homosexuals and in most of these cases, the attack led to sexual relationship with the student.

When these numbers are added to another 347 substantiated sex abuse cases that have been probed by the Board of Education’s Office of Special Investigation between January 2000 and July 20, 2001, the statistics become even more staggering.

When The Post added the OSI’s 327 cases to Stancik’s 117 substantiated cases of sexual abuse over two-and-a-half years, it was discovered that least one child is sexually abused by a school employee every day.

The Board of Education could not provide OSI’s numbers for 1999.

Stancik’s office investigates the most serious – and often criminal – offenses, while the OSI investigates all other accusations, officials said.

Teachers awaiting the resolution of sex abuse charges are placed in administrative slots at Martin Luther King HS in Manhattan, Edward R. Murrow HS in Brooklyn, and Theodore Rosevelt and Herbert Lehman high schools in The Bronx.